ARR 3.0 not caching many objects

Hi everyone

I'm using ARR 3.0 to reverse proxy a site, and it appears that only certain objects are being cached. I have cache override dules to explicitly cache everything for 3 minutes, but if a URL ends in / I always get X-ARR-CACHE-HIT=0.

Example http://www.domain.com/pages/news/   will always have a cache miss.

However, http://www.domain.com/page/news/pic1.jpg will experience cache hits.

Any ideas what's going on there?

Thanks